Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
Typically, a light scanning device is employed for exposure of image carriers such as a photoreceptor drums in an image forming apparatus such as a printer and a copier. A typical light scanning device includes a light source, and a polygon mirror that reflects a light beam emitted from the light source to scan surfaces of the image carriers in a main-scanning direction.
Image forming apparatuses in recent years have been achieving a high printing speed and a high resolution. This increases a desire for a higher scanning speed of a light scanning device. For the desire for the higher speed, increase of a rotation speed of a polygon mirror is considered. However, the increase of the rotation speed of the polygon mirror is restricted by various causes such as a performance of a motor that drives the polygon mirror, and heat of bearing. Thus, it has been developed that disposing a plurality of light-emitting elements in one light source to achieve a multibeam-type light scanning device that emits a plurality of light beams to image carriers from the one light source.
This light scanning device typically includes an aperture that regulates an expanded width in a direction corresponding to the main-scanning direction of the respective light beams emitted from the light source. The aperture includes a slit-shaped hole bored on a plate-shaped material. The aperture is located, for example, at a position at which the respective light beams intersect one another.
While the above-described light scanning device has a configuration where an optical path from the light source to the polygon mirror has a straight line shape, there is also known a light scanning device, as another example, having a configuration where a reflection mirror is located in the optical path to constitute an optical path in a polygonal line shape.